Field of the Invention
The present invention relates to a circuit substrate in which a build-up layer is laminated on a core substrate that has a cavity, and to a method for manufacturing the circuit substrate.
Description of Background Art
Japanese Patent Laid-Open Publication No. 2013-135168 describes a circuit substrate in which both front and back surfaces of a metal block accommodated in a cavity are fixed by insulating resin layers in build-up layers. The entire contents of this publication are incorporated herein by reference.